Checksum_Verification
    Nochecksum_Verification

    Requests that the page checksum be verified for each page copied.
    The default is to perform this verification.

    The Checksum_Verification qualifier uses significant CPU
    resources but can provide an extra measure of confidence in the
    quality of the data being copied. For offline copy operations,
    the additional CPU cost of using the Checksum_Verification
    qualifier might not be justified unless you are experiencing
    or have experienced disk, HSC, or CI port hardware problems. One
    symptom of these problems is pages being logged to the corrupt
    page table (CPT).

    For online copy operations, use of the Checksum_Verification
    qualifier offers an additional level of data security when the
    database employs disk striping or RAID (redundant arrays of
    inexpensive disks) technology. These technologies fragment data
    over several disk drives, and use of the Checksum_Verification
    qualifier permits Oracle RMU to detect the possibility that
    the data it is reading from these disks has been only partially
    updated. If you use either of these technologies, you should use
    the Checksum_Verification qualifier.

    Note, however, that if you specify the Nochecksum qualifier, and
    undetected corruptions exist in your database, the corruptions
    are included in the copied file. Such a corruption might be
    difficult to recover from, especially if it is not detected until
    weeks or months after the copy operation is performed.

    Overall, Oracle Corporation recommends that you use the Checksum_
    Verification qualifier with all copy operations where integrity
    of the data is essential.